Issue 57

M. Bentahar et alii, Frattura ed Integrità Strutturale, 57 (2021) 182-194; DOI: 10.3221/IGF-ESIS.57.15

a)

b)

c) Figure 8: The evolution of the FIC as a function of time increment with COF a) 0.1, b) 0.3 and c) 0.6 α = 0°.

The variation of the stress intensity factor as a function of the increment of the cracking time in fretting fatigue, for the model studied is presented on Fig. 8. One uses the various crack lengths (a) = 0.1, 0.5 and 1.0 mm and coefficient of friction 0.6 for the problem of fritting fatigue. Indeed, we notice that the increase in the time increment causes an increase in K I , and a decrease in K II of the same length and the same coefficient of friction. In addition, the increase in the coefficient of friction in the studied case α = 0 ° causes a decrease in K I and K II . These results were obtained by Sallam et al [30] in the case of the effects of the coefficient of friction on the stress intensity factor concerning the K I . The rate of increase of K II is small compared to K I . Fig. 9 shows the evolution of the integral of the contour (J) as a function of the time increment for the cases of COF = 0.1, 0.3 and 0.6 between the three cases of lengths a = 0.1, 0.5 and 01mm, at from this comparison. The first three values are almost zero and linear. It can also be observed that, with the increase of the time increment, there is an increase in (J) of the same length and the same coefficient of friction from the third time increment. However, there is a decrease in the results of (J) for different friction coefficients between them. Fretting fatigue from an inclined crack The following model shows the fatigue fretting of two parts in contact with each other and contains a crack inclined by the angle α = 15 °, 30 ° and 45 ° with a coefficient of friction 0.6. The SIF evolution as a function of the time increment with a friction coefficient 0.6 is indicated in (Fig.11). This comparison is carried out on the different crack lengths for a = 0.1, 0.5 and 01mm and the angle inclination α = 15 ° (Fig.11a), α = 30 ° (Fig.11b) and α = 45 ° (Fig.11c) for the fretting fatigue model. In addition, the increase in the increment time causes a decrease in K I and an increase in K II on the contrary for the comparison of the results obtained

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